High pitched squeal with high gain amp?

joafink2

Member
I tried my FM9 with my KSR Gemini 100 watt amp last night. When I put the Gemini on the lead channel and engage the bright switch, I get this odd high pitched squeal. When I disengage the bright switch on the amp, the high pitched sound goes away. The amp does not behave this way without the FM9, so I know it’s some type of interaction between the FM9 and Gemini.

Could this be a tube related issue? Or some electrical interaction with the FM9 and Gemini? Neither the FM9 or the Gemini make this sound separate from each other. Any advice on things I could try would be much appreciated.
 
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Not sure what you mean by blue mode(I do not have an fm9) but patches with high gain and lots of treble can get a high pitch feedback from fr tweeters.
 
Ok so not frfr. How did you connect the fm9? How did you set up the fm9 preset. if you bypass the fm9 does the volume of your amp signal change?

Signal is guitar>input1>effects>output 3>amp.

I did some more experimenting. It only happens when the USB is connected from my Macbook to the FM9 for FM9 Edit. Is there some setting I should change on the FM9 that can help lessen this electrical interaction?
 
Is there some setting I should change on the FM9 that can help lessen this electrical interaction?
I do not have an fm9, but I do not think there would be. Computers do emit efi, more than likely the bright switch amplifies this. I wouls just unplug the usb, should not need it after presets are set up.
 
Do you use humbuster cables? if not, they may help. I know they help using the effects loop, not sure about straight into the guitar input.
 
Do you use humbuster cables? if not, they may help. I know they help using the effects loop, not sure about straight into the guitar input.
Humbuster cables won't help when used as a guitar cord. They need specialized outputs (Fractal's 1/4" outputs) in order to work.
 
Humbuster cables won't help when used as a guitar cord. They need specialized outputs (Fractal's 1/4" outputs) in order to work.
Could humbuster cable help from the fm9 to amp?
In this configuration
 
Signal is guitar>input1>effects>output 3>amp.

I did some more experimenting. It only happens when the USB is connected from my Macbook to the FM9 for FM9 Edit. Is there some setting I should change on the FM9 that can help lessen this electrical interaction?

Does the noise stop if you disconnect the mains power supply and run your MacBook on battery?
 
Could humbuster cable help from the fm9 to amp?
In this configuration
They could help if you had some hum to get rid of, but they probably wouldn’t do much with the squealing you’re trying to fix.

Do you still get the squeal when your guitar’s volume knob is all the way down?
 
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